1. Field of the Invention
The present invention relates to a ratchet having an improved driving member which also incorporates a labor saving design. More particularly, the ratchet has a simplified drive head having a rotatable insert and an improved stop mechanism.
2. Description of the Related Prior Art
Conventional ratchet wrenches continue to need improvement in their durability and utility. Recently, the prior art focused on a labor saving structure in which the operator avoided exerting a large force to drive the handle to achieve the purpose of releasing or locking the workpiece, such as in U.S. Pat. No. 6,308,594. The present invention also aims to achieve this goal.
In doing so, however, the prior ratchet wrenches exhibit failure due to the rather weak locking mechanisms. Further, such prior ratchets are limited in torque by their locking mechanism. When confronted with a tight spot and well locked threaded member, the operator has to exert a large force for driving the handle which in turn applies significant force on the internal locking members of the head and due to their design are more subject to failure.
An objective of the present invention is to provide a ratchet with increased longevity while maintaining a labor saving purpose by the principle of leverage.
It another object to provide an improved ratchet wrench design.
Accordingly, the present invention is directed to a ratchet for rotating a threaded member. The ratchet includes an elongated member having a first end forming a handle and a second end, the second end including an open receiving surface therein. An insert is disposed within the open receiving surface and of a size smaller than the open receiving surface, wherein a portion of the open receiving surface includes a bearing surface against which the insert rotates, the insert configured for engaging the threaded member to enable rotation thereof.
A movable stop is also operably disposed within another portion of the open receiving surface adjacent the insert and the bearing surface in a manner such that when the insert is caused to rotate in one direction relative to the bearing surface the stop is frictionally drawn into lodging engagement with the insert and bearing surface to preclude further rotation of the insert and fixably secure relative position between the insert and the bearing surface whereby the rotation of the threaded member is effected, and when the insert is caused to rotate in an opposite direction, the stop is driven into a dislodged position.
In a preferred embodiment, the bearing surface extends partway along a perimeter of the open receiving surface against the insert, thereby leaving a portion of the perimeter contacting against the bearing surface and another portion out of contact with the bearing surface there being defined a first separation point between the bearing surface and the insert and a second separation point between the bearing surface and the insert. The stop is movable between a first position wherein the stop is disposed adjacent the first separation point and a second position wherein the stop is disposed adjacent the second separation point, the ratchet thus providing positive clockwise and counterclockwise rotation of the threaded member when switched between the two positions. The stop can be generally V-shaped.